2 * Low level x86 E820 memory map handling functions.
4 * The firmware and bootloader passes us the "E820 table", which is the primary
5 * physical memory layout description available about x86 systems.
7 * The kernel takes the E820 memory layout and optionally modifies it with
8 * quirks and other tweaks, and feeds that into the generic Linux memory
9 * allocation code routines via a platform independent interface (memblock, etc.).
11 #include <linux/crash_dump.h>
12 #include <linux/bootmem.h>
13 #include <linux/suspend.h>
14 #include <linux/acpi.h>
15 #include <linux/firmware-map.h>
16 #include <linux/memblock.h>
17 #include <linux/sort.h>
19 #include <asm/e820/api.h>
20 #include <asm/setup.h>
23 * We organize the E820 table into three main data structures:
25 * - 'e820_table_firmware': the original firmware version passed to us by the
26 * bootloader - not modified by the kernel. It is composed of two parts:
27 * the first 128 E820 memory entries in boot_params.e820_table and the remaining
28 * (if any) entries of the SETUP_E820_EXT nodes. We use this to:
30 * - inform the user about the firmware's notion of memory layout
31 * via /sys/firmware/memmap
33 * - the hibernation code uses it to generate a kernel-independent MD5
34 * fingerprint of the physical memory layout of a system.
36 * - 'e820_table_kexec': a slightly modified (by the kernel) firmware version
37 * passed to us by the bootloader - the major difference between
38 * e820_table_firmware[] and this one is that, the latter marks the setup_data
39 * list created by the EFI boot stub as reserved, so that kexec can reuse the
40 * setup_data information in the second kernel. Besides, e820_table_kexec[]
41 * might also be modified by the kexec itself to fake a mptable.
44 * - kexec, which is a bootloader in disguise, uses the original E820
45 * layout to pass to the kexec-ed kernel. This way the original kernel
46 * can have a restricted E820 map while the kexec()-ed kexec-kernel
47 * can have access to full memory - etc.
49 * - 'e820_table': this is the main E820 table that is massaged by the
50 * low level x86 platform code, or modified by boot parameters, before
51 * passed on to higher level MM layers.
53 * Once the E820 map has been converted to the standard Linux memory layout
54 * information its role stops - modifying it has no effect and does not get
55 * re-propagated. So itsmain role is a temporary bootstrap storage of firmware
56 * specific memory layout data during early bootup.
58 static struct e820_table e820_table_init __initdata;
59 static struct e820_table e820_table_kexec_init __initdata;
60 static struct e820_table e820_table_firmware_init __initdata;
62 struct e820_table *e820_table __refdata = &e820_table_init;
63 struct e820_table *e820_table_kexec __refdata = &e820_table_kexec_init;
64 struct e820_table *e820_table_firmware __refdata = &e820_table_firmware_init;
66 /* For PCI or other memory-mapped resources */
67 unsigned long pci_mem_start = 0xaeedbabe;
69 EXPORT_SYMBOL(pci_mem_start);
73 * This function checks if any part of the range <start,end> is mapped
76 bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
80 for (i = 0; i < e820_table->nr_entries; i++) {
81 struct e820_entry *entry = &e820_table->entries[i];
83 if (type && entry->type != type)
85 if (entry->addr >= end || entry->addr + entry->size <= start)
91 EXPORT_SYMBOL_GPL(e820__mapped_any);
94 * This function checks if the entire <start,end> range is mapped with 'type'.
96 * Note: this function only works correctly once the E820 table is sorted and
97 * not-overlapping (at least for the range specified), which is the case normally.
99 bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
103 for (i = 0; i < e820_table->nr_entries; i++) {
104 struct e820_entry *entry = &e820_table->entries[i];
106 if (type && entry->type != type)
109 /* Is the region (part) in overlap with the current region? */
110 if (entry->addr >= end || entry->addr + entry->size <= start)
114 * If the region is at the beginning of <start,end> we move
115 * 'start' to the end of the region since it's ok until there
117 if (entry->addr <= start)
118 start = entry->addr + entry->size;
121 * If 'start' is now at or beyond 'end', we're done, full
122 * coverage of the desired range exists:
131 * Add a memory region to the kernel E820 map.
133 static void __init __e820__range_add(struct e820_table *table, u64 start, u64 size, enum e820_type type)
135 int x = table->nr_entries;
137 if (x >= ARRAY_SIZE(table->entries)) {
138 pr_err("e820: too many entries; ignoring [mem %#010llx-%#010llx]\n", start, start + size - 1);
142 table->entries[x].addr = start;
143 table->entries[x].size = size;
144 table->entries[x].type = type;
148 void __init e820__range_add(u64 start, u64 size, enum e820_type type)
150 __e820__range_add(e820_table, start, size, type);
153 static void __init e820_print_type(enum e820_type type)
156 case E820_TYPE_RAM: /* Fall through: */
157 case E820_TYPE_RESERVED_KERN: pr_cont("usable"); break;
158 case E820_TYPE_RESERVED: pr_cont("reserved"); break;
159 case E820_TYPE_ACPI: pr_cont("ACPI data"); break;
160 case E820_TYPE_NVS: pr_cont("ACPI NVS"); break;
161 case E820_TYPE_UNUSABLE: pr_cont("unusable"); break;
162 case E820_TYPE_PMEM: /* Fall through: */
163 case E820_TYPE_PRAM: pr_cont("persistent (type %u)", type); break;
164 default: pr_cont("type %u", type); break;
168 void __init e820__print_table(char *who)
172 for (i = 0; i < e820_table->nr_entries; i++) {
173 pr_info("%s: [mem %#018Lx-%#018Lx] ", who,
174 e820_table->entries[i].addr,
175 e820_table->entries[i].addr + e820_table->entries[i].size - 1);
177 e820_print_type(e820_table->entries[i].type);
183 * Sanitize an E820 map.
185 * Some E820 layouts include overlapping entries. The following
186 * replaces the original E820 map with a new one, removing overlaps,
187 * and resolving conflicting memory types in favor of highest
190 * The input parameter 'entries' points to an array of 'struct
191 * e820_entry' which on entry has elements in the range [0, *nr_entries)
192 * valid, and which has space for up to max_nr_entries entries.
193 * On return, the resulting sanitized E820 map entries will be in
194 * overwritten in the same location, starting at 'entries'.
196 * The integer pointed to by nr_entries must be valid on entry (the
197 * current number of valid entries located at 'entries'). If the
198 * sanitizing succeeds the *nr_entries will be updated with the new
199 * number of valid entries (something no more than max_nr_entries).
201 * The return value from e820__update_table() is zero if it
202 * successfully 'sanitized' the map entries passed in, and is -1
203 * if it did nothing, which can happen if either of (1) it was
204 * only passed one map entry, or (2) any of the input map entries
205 * were invalid (start + size < start, meaning that the size was
206 * so big the described memory range wrapped around through zero.)
208 * Visually we're performing the following
209 * (1,2,3,4 = memory types)...
211 * Sample memory map (w/overlaps):
212 * ____22__________________
213 * ______________________4_
214 * ____1111________________
215 * _44_____________________
216 * 11111111________________
217 * ____________________33__
218 * ___________44___________
219 * __________33333_________
220 * ______________22________
221 * ___________________2222_
222 * _________111111111______
223 * _____________________11_
224 * _________________4______
226 * Sanitized equivalent (no overlap):
227 * 1_______________________
228 * _44_____________________
229 * ___1____________________
230 * ____22__________________
231 * ______11________________
232 * _________1______________
233 * __________3_____________
234 * ___________44___________
235 * _____________33_________
236 * _______________2________
237 * ________________1_______
238 * _________________4______
239 * ___________________2____
240 * ____________________33__
241 * ______________________4_
243 struct change_member {
244 /* Pointer to the original entry: */
245 struct e820_entry *entry;
246 /* Address for this change point: */
247 unsigned long long addr;
250 static struct change_member change_point_list[2*E820_MAX_ENTRIES] __initdata;
251 static struct change_member *change_point[2*E820_MAX_ENTRIES] __initdata;
252 static struct e820_entry *overlap_list[E820_MAX_ENTRIES] __initdata;
253 static struct e820_entry new_entries[E820_MAX_ENTRIES] __initdata;
255 static int __init cpcompare(const void *a, const void *b)
257 struct change_member * const *app = a, * const *bpp = b;
258 const struct change_member *ap = *app, *bp = *bpp;
261 * Inputs are pointers to two elements of change_point[]. If their
262 * addresses are not equal, their difference dominates. If the addresses
263 * are equal, then consider one that represents the end of its region
264 * to be greater than one that does not.
266 if (ap->addr != bp->addr)
267 return ap->addr > bp->addr ? 1 : -1;
269 return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
272 int __init e820__update_table(struct e820_table *table)
274 struct e820_entry *entries = table->entries;
275 u32 max_nr_entries = ARRAY_SIZE(table->entries);
276 enum e820_type current_type, last_type;
277 unsigned long long last_addr;
278 u32 new_nr_entries, overlap_entries;
279 u32 i, chg_idx, chg_nr;
281 /* If there's only one memory region, don't bother: */
282 if (table->nr_entries < 2)
285 BUG_ON(table->nr_entries > max_nr_entries);
287 /* Bail out if we find any unreasonable addresses in the map: */
288 for (i = 0; i < table->nr_entries; i++) {
289 if (entries[i].addr + entries[i].size < entries[i].addr)
293 /* Create pointers for initial change-point information (for sorting): */
294 for (i = 0; i < 2 * table->nr_entries; i++)
295 change_point[i] = &change_point_list[i];
298 * Record all known change-points (starting and ending addresses),
299 * omitting empty memory regions:
302 for (i = 0; i < table->nr_entries; i++) {
303 if (entries[i].size != 0) {
304 change_point[chg_idx]->addr = entries[i].addr;
305 change_point[chg_idx++]->entry = &entries[i];
306 change_point[chg_idx]->addr = entries[i].addr + entries[i].size;
307 change_point[chg_idx++]->entry = &entries[i];
312 /* Sort change-point list by memory addresses (low -> high): */
313 sort(change_point, chg_nr, sizeof(*change_point), cpcompare, NULL);
315 /* Create a new memory map, removing overlaps: */
316 overlap_entries = 0; /* Number of entries in the overlap table */
317 new_nr_entries = 0; /* Index for creating new map entries */
318 last_type = 0; /* Start with undefined memory type */
319 last_addr = 0; /* Start with 0 as last starting address */
321 /* Loop through change-points, determining effect on the new map: */
322 for (chg_idx = 0; chg_idx < chg_nr; chg_idx++) {
323 /* Keep track of all overlapping entries */
324 if (change_point[chg_idx]->addr == change_point[chg_idx]->entry->addr) {
325 /* Add map entry to overlap list (> 1 entry implies an overlap) */
326 overlap_list[overlap_entries++] = change_point[chg_idx]->entry;
328 /* Remove entry from list (order independent, so swap with last): */
329 for (i = 0; i < overlap_entries; i++) {
330 if (overlap_list[i] == change_point[chg_idx]->entry)
331 overlap_list[i] = overlap_list[overlap_entries-1];
336 * If there are overlapping entries, decide which
337 * "type" to use (larger value takes precedence --
338 * 1=usable, 2,3,4,4+=unusable)
341 for (i = 0; i < overlap_entries; i++) {
342 if (overlap_list[i]->type > current_type)
343 current_type = overlap_list[i]->type;
346 /* Continue building up new map based on this information: */
347 if (current_type != last_type || current_type == E820_TYPE_PRAM) {
348 if (last_type != 0) {
349 new_entries[new_nr_entries].size = change_point[chg_idx]->addr - last_addr;
350 /* Move forward only if the new size was non-zero: */
351 if (new_entries[new_nr_entries].size != 0)
352 /* No more space left for new entries? */
353 if (++new_nr_entries >= max_nr_entries)
356 if (current_type != 0) {
357 new_entries[new_nr_entries].addr = change_point[chg_idx]->addr;
358 new_entries[new_nr_entries].type = current_type;
359 last_addr = change_point[chg_idx]->addr;
361 last_type = current_type;
365 /* Copy the new entries into the original location: */
366 memcpy(entries, new_entries, new_nr_entries*sizeof(*entries));
367 table->nr_entries = new_nr_entries;
372 static int __init __append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
374 struct boot_e820_entry *entry = entries;
377 u64 start = entry->addr;
378 u64 size = entry->size;
379 u64 end = start + size - 1;
380 u32 type = entry->type;
382 /* Ignore the entry on 64-bit overflow: */
383 if (start > end && likely(size))
386 e820__range_add(start, size, type);
395 * Copy the BIOS E820 map into a safe place.
397 * Sanity-check it while we're at it..
399 * If we're lucky and live on a modern system, the setup code
400 * will have given us a memory map that we can use to properly
401 * set up memory. If we aren't, we'll fake a memory map.
403 static int __init append_e820_table(struct boot_e820_entry *entries, u32 nr_entries)
405 /* Only one memory region (or negative)? Ignore it */
409 return __append_e820_table(entries, nr_entries);
413 __e820__range_update(struct e820_table *table, u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
417 u64 real_updated_size = 0;
419 BUG_ON(old_type == new_type);
421 if (size > (ULLONG_MAX - start))
422 size = ULLONG_MAX - start;
425 printk(KERN_DEBUG "e820: update [mem %#010Lx-%#010Lx] ", start, end - 1);
426 e820_print_type(old_type);
428 e820_print_type(new_type);
431 for (i = 0; i < table->nr_entries; i++) {
432 struct e820_entry *entry = &table->entries[i];
433 u64 final_start, final_end;
436 if (entry->type != old_type)
439 entry_end = entry->addr + entry->size;
441 /* Completely covered by new range? */
442 if (entry->addr >= start && entry_end <= end) {
443 entry->type = new_type;
444 real_updated_size += entry->size;
448 /* New range is completely covered? */
449 if (entry->addr < start && entry_end > end) {
450 __e820__range_add(table, start, size, new_type);
451 __e820__range_add(table, end, entry_end - end, entry->type);
452 entry->size = start - entry->addr;
453 real_updated_size += size;
457 /* Partially covered: */
458 final_start = max(start, entry->addr);
459 final_end = min(end, entry_end);
460 if (final_start >= final_end)
463 __e820__range_add(table, final_start, final_end - final_start, new_type);
465 real_updated_size += final_end - final_start;
468 * Left range could be head or tail, so need to update
471 entry->size -= final_end - final_start;
472 if (entry->addr < final_start)
475 entry->addr = final_end;
477 return real_updated_size;
480 u64 __init e820__range_update(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
482 return __e820__range_update(e820_table, start, size, old_type, new_type);
485 static u64 __init e820__range_update_kexec(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
487 return __e820__range_update(e820_table_kexec, start, size, old_type, new_type);
490 /* Remove a range of memory from the E820 table: */
491 u64 __init e820__range_remove(u64 start, u64 size, enum e820_type old_type, bool check_type)
495 u64 real_removed_size = 0;
497 if (size > (ULLONG_MAX - start))
498 size = ULLONG_MAX - start;
501 printk(KERN_DEBUG "e820: remove [mem %#010Lx-%#010Lx] ", start, end - 1);
503 e820_print_type(old_type);
506 for (i = 0; i < e820_table->nr_entries; i++) {
507 struct e820_entry *entry = &e820_table->entries[i];
508 u64 final_start, final_end;
511 if (check_type && entry->type != old_type)
514 entry_end = entry->addr + entry->size;
516 /* Completely covered? */
517 if (entry->addr >= start && entry_end <= end) {
518 real_removed_size += entry->size;
519 memset(entry, 0, sizeof(*entry));
523 /* Is the new range completely covered? */
524 if (entry->addr < start && entry_end > end) {
525 e820__range_add(end, entry_end - end, entry->type);
526 entry->size = start - entry->addr;
527 real_removed_size += size;
531 /* Partially covered: */
532 final_start = max(start, entry->addr);
533 final_end = min(end, entry_end);
534 if (final_start >= final_end)
537 real_removed_size += final_end - final_start;
540 * Left range could be head or tail, so need to update
543 entry->size -= final_end - final_start;
544 if (entry->addr < final_start)
547 entry->addr = final_end;
549 return real_removed_size;
552 void __init e820__update_table_print(void)
554 if (e820__update_table(e820_table))
557 pr_info("e820: modified physical RAM map:\n");
558 e820__print_table("modified");
561 static void __init e820__update_table_kexec(void)
563 e820__update_table(e820_table_kexec);
566 #define MAX_GAP_END 0x100000000ull
569 * Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
571 static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsize)
573 unsigned long long last = MAX_GAP_END;
574 int i = e820_table->nr_entries;
578 unsigned long long start = e820_table->entries[i].addr;
579 unsigned long long end = start + e820_table->entries[i].size;
582 * Since "last" is at most 4GB, we know we'll
583 * fit in 32 bits if this condition is true:
586 unsigned long gap = last - end;
588 if (gap >= *gapsize) {
601 * Search for the biggest gap in the low 32 bits of the E820
602 * memory space. We pass this space to the PCI subsystem, so
603 * that it can assign MMIO resources for hotplug or
604 * unconfigured devices in.
606 * Hopefully the BIOS let enough space left.
608 __init void e820__setup_pci_gap(void)
610 unsigned long gapstart, gapsize;
614 found = e820_search_gap(&gapstart, &gapsize);
618 gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
620 "e820: Cannot find an available gap in the 32-bit address range\n"
621 "e820: PCI devices with unassigned 32-bit BARs may not work!\n");
623 gapstart = 0x10000000;
628 * e820__reserve_resources_late() protects stolen RAM already:
630 pci_mem_start = gapstart;
632 pr_info("e820: [mem %#010lx-%#010lx] available for PCI devices\n", gapstart, gapstart + gapsize - 1);
636 * Called late during init, in free_initmem().
638 * Initial e820_table and e820_table_kexec are largish __initdata arrays.
640 * Copy them to a (usually much smaller) dynamically allocated area that is
641 * sized precisely after the number of e820 entries.
643 * This is done after we've performed all the fixes and tweaks to the tables.
644 * All functions which modify them are __init functions, which won't exist
645 * after free_initmem().
647 __init void e820__reallocate_tables(void)
649 struct e820_table *n;
652 size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table->nr_entries;
653 n = kmalloc(size, GFP_KERNEL);
655 memcpy(n, e820_table, size);
658 size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_kexec->nr_entries;
659 n = kmalloc(size, GFP_KERNEL);
661 memcpy(n, e820_table_kexec, size);
662 e820_table_kexec = n;
664 size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry)*e820_table_firmware->nr_entries;
665 n = kmalloc(size, GFP_KERNEL);
667 memcpy(n, e820_table_firmware, size);
668 e820_table_firmware = n;
672 * Because of the small fixed size of struct boot_params, only the first
673 * 128 E820 memory entries are passed to the kernel via boot_params.e820_table,
674 * the remaining (if any) entries are passed via the SETUP_E820_EXT node of
675 * struct setup_data, which is parsed here.
677 void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len)
680 struct boot_e820_entry *extmap;
681 struct setup_data *sdata;
683 sdata = early_memremap(phys_addr, data_len);
684 entries = sdata->len / sizeof(*extmap);
685 extmap = (struct boot_e820_entry *)(sdata->data);
687 __append_e820_table(extmap, entries);
688 e820__update_table(e820_table);
690 memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
691 memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
693 early_memunmap(sdata, data_len);
694 pr_info("e820: extended physical RAM map:\n");
695 e820__print_table("extended");
699 * Find the ranges of physical addresses that do not correspond to
700 * E820 RAM areas and register the corresponding pages as 'nosave' for
701 * hibernation (32-bit) or software suspend and suspend to RAM (64-bit).
703 * This function requires the E820 map to be sorted and without any
704 * overlapping entries.
706 void __init e820__register_nosave_regions(unsigned long limit_pfn)
709 unsigned long pfn = 0;
711 for (i = 0; i < e820_table->nr_entries; i++) {
712 struct e820_entry *entry = &e820_table->entries[i];
714 if (pfn < PFN_UP(entry->addr))
715 register_nosave_region(pfn, PFN_UP(entry->addr));
717 pfn = PFN_DOWN(entry->addr + entry->size);
719 if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
720 register_nosave_region(PFN_UP(entry->addr), pfn);
722 if (pfn >= limit_pfn)
729 * Register ACPI NVS memory regions, so that we can save/restore them during
730 * hibernation and the subsequent resume:
732 static int __init e820__register_nvs_regions(void)
736 for (i = 0; i < e820_table->nr_entries; i++) {
737 struct e820_entry *entry = &e820_table->entries[i];
739 if (entry->type == E820_TYPE_NVS)
740 acpi_nvs_register(entry->addr, entry->size);
745 core_initcall(e820__register_nvs_regions);
749 * Allocate the requested number of bytes with the requsted alignment
750 * and return (the physical address) to the caller. Also register this
751 * range in the 'kexec' E820 table as a reserved range.
753 * This allows kexec to fake a new mptable, as if it came from the real
756 u64 __init e820__memblock_alloc_reserved(u64 size, u64 align)
760 addr = __memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
762 e820__range_update_kexec(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
763 pr_info("e820: update e820_table_kexec for e820__memblock_alloc_reserved()\n");
764 e820__update_table_kexec();
771 # ifdef CONFIG_X86_PAE
772 # define MAX_ARCH_PFN (1ULL<<(36-PAGE_SHIFT))
774 # define MAX_ARCH_PFN (1ULL<<(32-PAGE_SHIFT))
776 #else /* CONFIG_X86_32 */
777 # define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
781 * Find the highest page frame number we have available
783 static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type type)
786 unsigned long last_pfn = 0;
787 unsigned long max_arch_pfn = MAX_ARCH_PFN;
789 for (i = 0; i < e820_table->nr_entries; i++) {
790 struct e820_entry *entry = &e820_table->entries[i];
791 unsigned long start_pfn;
792 unsigned long end_pfn;
794 if (entry->type != type)
797 start_pfn = entry->addr >> PAGE_SHIFT;
798 end_pfn = (entry->addr + entry->size) >> PAGE_SHIFT;
800 if (start_pfn >= limit_pfn)
802 if (end_pfn > limit_pfn) {
803 last_pfn = limit_pfn;
806 if (end_pfn > last_pfn)
810 if (last_pfn > max_arch_pfn)
811 last_pfn = max_arch_pfn;
813 pr_info("e820: last_pfn = %#lx max_arch_pfn = %#lx\n",
814 last_pfn, max_arch_pfn);
818 unsigned long __init e820__end_of_ram_pfn(void)
820 return e820_end_pfn(MAX_ARCH_PFN, E820_TYPE_RAM);
823 unsigned long __init e820__end_of_low_ram_pfn(void)
825 return e820_end_pfn(1UL << (32 - PAGE_SHIFT), E820_TYPE_RAM);
828 static void __init early_panic(char *msg)
834 static int userdef __initdata;
836 /* The "mem=nopentium" boot option disables 4MB page tables on 32-bit kernels: */
837 static int __init parse_memopt(char *p)
844 if (!strcmp(p, "nopentium")) {
846 setup_clear_cpu_cap(X86_FEATURE_PSE);
849 pr_warn("mem=nopentium ignored! (only supported on x86_32)\n");
855 mem_size = memparse(p, &p);
857 /* Don't remove all memory when getting "mem={invalid}" parameter: */
861 e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
865 early_param("mem", parse_memopt);
867 static int __init parse_memmap_one(char *p)
870 u64 start_at, mem_size;
875 if (!strncmp(p, "exactmap", 8)) {
876 #ifdef CONFIG_CRASH_DUMP
878 * If we are doing a crash dump, we still need to know
879 * the real memory size before the original memory map is
882 saved_max_pfn = e820__end_of_ram_pfn();
884 e820_table->nr_entries = 0;
890 mem_size = memparse(p, &p);
896 start_at = memparse(p+1, &p);
897 e820__range_add(start_at, mem_size, E820_TYPE_RAM);
898 } else if (*p == '#') {
899 start_at = memparse(p+1, &p);
900 e820__range_add(start_at, mem_size, E820_TYPE_ACPI);
901 } else if (*p == '$') {
902 start_at = memparse(p+1, &p);
903 e820__range_add(start_at, mem_size, E820_TYPE_RESERVED);
904 } else if (*p == '!') {
905 start_at = memparse(p+1, &p);
906 e820__range_add(start_at, mem_size, E820_TYPE_PRAM);
908 e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1);
911 return *p == '\0' ? 0 : -EINVAL;
914 static int __init parse_memmap_opt(char *str)
917 char *k = strchr(str, ',');
922 parse_memmap_one(str);
928 early_param("memmap", parse_memmap_opt);
931 * Reserve all entries from the bootloader's extensible data nodes list,
932 * because if present we are going to use it later on to fetch e820
935 void __init e820__reserve_setup_data(void)
937 struct setup_data *data;
940 pa_data = boot_params.hdr.setup_data;
945 data = early_memremap(pa_data, sizeof(*data));
946 e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
947 e820__range_update_kexec(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
948 pa_data = data->next;
949 early_memunmap(data, sizeof(*data));
952 e820__update_table(e820_table);
953 e820__update_table(e820_table_kexec);
955 pr_info("extended physical RAM map:\n");
956 e820__print_table("reserve setup_data");
960 * Called after parse_early_param(), after early parameters (such as mem=)
961 * have been processed, in which case we already have an E820 table filled in
962 * via the parameter callback function(s), but it's not sorted and printed yet:
964 void __init e820__finish_early_params(void)
967 if (e820__update_table(e820_table) < 0)
968 early_panic("Invalid user supplied memory map");
970 pr_info("e820: user-defined physical RAM map:\n");
971 e820__print_table("user");
975 static const char *__init e820_type_to_string(struct e820_entry *entry)
977 switch (entry->type) {
978 case E820_TYPE_RESERVED_KERN: /* Fall-through: */
979 case E820_TYPE_RAM: return "System RAM";
980 case E820_TYPE_ACPI: return "ACPI Tables";
981 case E820_TYPE_NVS: return "ACPI Non-volatile Storage";
982 case E820_TYPE_UNUSABLE: return "Unusable memory";
983 case E820_TYPE_PRAM: return "Persistent Memory (legacy)";
984 case E820_TYPE_PMEM: return "Persistent Memory";
985 case E820_TYPE_RESERVED: return "Reserved";
986 default: return "Unknown E820 type";
990 static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry)
992 switch (entry->type) {
993 case E820_TYPE_RESERVED_KERN: /* Fall-through: */
994 case E820_TYPE_RAM: return IORESOURCE_SYSTEM_RAM;
995 case E820_TYPE_ACPI: /* Fall-through: */
996 case E820_TYPE_NVS: /* Fall-through: */
997 case E820_TYPE_UNUSABLE: /* Fall-through: */
998 case E820_TYPE_PRAM: /* Fall-through: */
999 case E820_TYPE_PMEM: /* Fall-through: */
1000 case E820_TYPE_RESERVED: /* Fall-through: */
1001 default: return IORESOURCE_MEM;
1005 static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry)
1007 switch (entry->type) {
1008 case E820_TYPE_ACPI: return IORES_DESC_ACPI_TABLES;
1009 case E820_TYPE_NVS: return IORES_DESC_ACPI_NV_STORAGE;
1010 case E820_TYPE_PMEM: return IORES_DESC_PERSISTENT_MEMORY;
1011 case E820_TYPE_PRAM: return IORES_DESC_PERSISTENT_MEMORY_LEGACY;
1012 case E820_TYPE_RESERVED_KERN: /* Fall-through: */
1013 case E820_TYPE_RAM: /* Fall-through: */
1014 case E820_TYPE_UNUSABLE: /* Fall-through: */
1015 case E820_TYPE_RESERVED: /* Fall-through: */
1016 default: return IORES_DESC_NONE;
1020 static bool __init do_mark_busy(enum e820_type type, struct resource *res)
1022 /* this is the legacy bios/dos rom-shadow + mmio region */
1023 if (res->start < (1ULL<<20))
1027 * Treat persistent memory like device memory, i.e. reserve it
1028 * for exclusive use of a driver
1031 case E820_TYPE_RESERVED:
1032 case E820_TYPE_PRAM:
1033 case E820_TYPE_PMEM:
1035 case E820_TYPE_RESERVED_KERN:
1037 case E820_TYPE_ACPI:
1039 case E820_TYPE_UNUSABLE:
1046 * Mark E820 reserved areas as busy for the resource manager:
1049 static struct resource __initdata *e820_res;
1051 void __init e820__reserve_resources(void)
1054 struct resource *res;
1057 res = alloc_bootmem(sizeof(*res) * e820_table->nr_entries);
1060 for (i = 0; i < e820_table->nr_entries; i++) {
1061 struct e820_entry *entry = e820_table->entries + i;
1063 end = entry->addr + entry->size - 1;
1064 if (end != (resource_size_t)end) {
1068 res->start = entry->addr;
1070 res->name = e820_type_to_string(entry);
1071 res->flags = e820_type_to_iomem_type(entry);
1072 res->desc = e820_type_to_iores_desc(entry);
1075 * Don't register the region that could be conflicted with
1076 * PCI device BAR resources and insert them later in
1077 * pcibios_resource_survey():
1079 if (do_mark_busy(entry->type, res)) {
1080 res->flags |= IORESOURCE_BUSY;
1081 insert_resource(&iomem_resource, res);
1086 /* Expose the bootloader-provided memory layout to the sysfs. */
1087 for (i = 0; i < e820_table_firmware->nr_entries; i++) {
1088 struct e820_entry *entry = e820_table_firmware->entries + i;
1090 firmware_map_add_early(entry->addr, entry->addr + entry->size, e820_type_to_string(entry));
1095 * How much should we pad the end of RAM, depending on where it is?
1097 static unsigned long __init ram_alignment(resource_size_t pos)
1099 unsigned long mb = pos >> 20;
1101 /* To 64kB in the first megabyte */
1105 /* To 1MB in the first 16MB */
1109 /* To 64MB for anything above that */
1110 return 64*1024*1024;
1113 #define MAX_RESOURCE_SIZE ((resource_size_t)-1)
1115 void __init e820__reserve_resources_late(void)
1118 struct resource *res;
1121 for (i = 0; i < e820_table->nr_entries; i++) {
1122 if (!res->parent && res->end)
1123 insert_resource_expand_to_fit(&iomem_resource, res);
1128 * Try to bump up RAM regions to reasonable boundaries, to
1131 for (i = 0; i < e820_table->nr_entries; i++) {
1132 struct e820_entry *entry = &e820_table->entries[i];
1135 if (entry->type != E820_TYPE_RAM)
1138 start = entry->addr + entry->size;
1139 end = round_up(start, ram_alignment(start)) - 1;
1140 if (end > MAX_RESOURCE_SIZE)
1141 end = MAX_RESOURCE_SIZE;
1145 printk(KERN_DEBUG "e820: reserve RAM buffer [mem %#010llx-%#010llx]\n", start, end);
1146 reserve_region_with_split(&iomem_resource, start, end, "RAM buffer");
1151 * Pass the firmware (bootloader) E820 map to the kernel and process it:
1153 char *__init e820__memory_setup_default(void)
1155 char *who = "BIOS-e820";
1158 * Try to copy the BIOS-supplied E820-map.
1160 * Otherwise fake a memory map; one section from 0k->640k,
1161 * the next section from 1mb->appropriate_mem_k
1163 if (append_e820_table(boot_params.e820_table, boot_params.e820_entries) < 0) {
1166 /* Compare results from other methods and take the one that gives more RAM: */
1167 if (boot_params.alt_mem_k < boot_params.screen_info.ext_mem_k) {
1168 mem_size = boot_params.screen_info.ext_mem_k;
1171 mem_size = boot_params.alt_mem_k;
1175 e820_table->nr_entries = 0;
1176 e820__range_add(0, LOWMEMSIZE(), E820_TYPE_RAM);
1177 e820__range_add(HIGH_MEMORY, mem_size << 10, E820_TYPE_RAM);
1180 /* We just appended a lot of ranges, sanitize the table: */
1181 e820__update_table(e820_table);
1187 * Calls e820__memory_setup_default() in essence to pick up the firmware/bootloader
1188 * E820 map - with an optional platform quirk available for virtual platforms
1189 * to override this method of boot environment processing:
1191 void __init e820__memory_setup(void)
1195 /* This is a firmware interface ABI - make sure we don't break it: */
1196 BUILD_BUG_ON(sizeof(struct boot_e820_entry) != 20);
1198 who = x86_init.resources.memory_setup();
1200 memcpy(e820_table_kexec, e820_table, sizeof(*e820_table_kexec));
1201 memcpy(e820_table_firmware, e820_table, sizeof(*e820_table_firmware));
1203 pr_info("e820: BIOS-provided physical RAM map:\n");
1204 e820__print_table(who);
1207 void __init e820__memblock_setup(void)
1213 * The bootstrap memblock region count maximum is 128 entries
1214 * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
1215 * than that - so allow memblock resizing.
1217 * This is safe, because this call happens pretty late during x86 setup,
1218 * so we know about reserved memory regions already. (This is important
1219 * so that memblock resizing does no stomp over reserved areas.)
1221 memblock_allow_resize();
1223 for (i = 0; i < e820_table->nr_entries; i++) {
1224 struct e820_entry *entry = &e820_table->entries[i];
1226 end = entry->addr + entry->size;
1227 if (end != (resource_size_t)end)
1230 if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
1233 memblock_add(entry->addr, entry->size);
1236 /* Throw away partial pages: */
1237 memblock_trim_memory(PAGE_SIZE);
1239 memblock_dump_all();